Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Memory devices are semiconductor devices that are used to store digital information. One type of memory device is a static random access memory (SRAM) device, which is a memory device that does not require periodic refreshing to store information, as do dynamic random access memory (DRAM) devices. SRAM devices use bi-stable latching circuitry to store a bit of data. Some recent designs for SRAM devices utilize Fin Field Effect Transistors (FinFETs) as transistor devices of the SRAM cells. A FinFET is a transistor structure with a fin-like semiconductor channel that is raised vertically out of the semiconductor surface of an integrated circuit.
The semiconductor industry continues to improve the integration density of various electronic components by continual reductions in minimum feature size, which allow more components to be integrated into a given area. It is desirable in many applications to reduce the size of SRAM cells, to improve device performance, reduce power requirements, and allow more SRAM cells to be positioned within a given amount of surface area on an integrated circuit die.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.